| Prefabricated steel structure buildings adopt the design concept of "integration",which reduces energy consumption and environmental pollution through factory prefabrication and on-site installation,and is a green building that meets the requirements of energy conservation and emission reduction of buildings in China.In prefabricated steel structure buildings,H-beam is often used to connect the joints,but the square steel tubular column has better performance compared with H-beam column,its torsional stiffness and out-of-plane stiffness are greater,and the building applicability is stronger.The traditional connection methods of closed section column and beam joints,such as bolt through type and through partition type,will weaken the column to some extent.Therefore,this paper proposes a new type of joint: Square steel tubular column-H shaped steel beam connected with T-shaped steel and blind bolt.This kind of connection method can realize the single-side tightening of the column and beam,without causing unnecessary weakening to the closed section column,which is more convenient and fast.At present,there are few studies on blind bolt column and beam joint at home and abroad,and there is no systematic theory to guide the actual construction,so it is very significant to study the mechanical properties of this nodes.In this paper,the quasi-static test under monotonic load and cyclic load is carried out on the connection joints,and combine with ABAQUS finite element software verified the accuracy of experimental research and finite element simulation results.Obtained the load-displacement curve of the node,and analyzed the load-displacement curve of the node and the stress-strain state of the member.Then,on the basis of the BASE node,12 series of finite element models were derived by changing the structure of the node,and the mechanical properties of the nodes under different structures were simulated by finite element analysis.This paper mainly analyzed the influence of six structural measures on the mechanical properties of BASE node,such as column wall thickness,stiffener,Angle steel with double web,flange web of H-beam weakened and beam height reduced,drew the following conclusions:(1)Increasing the thickness of the column wall can obviously improve the initial rotational stiffness and ultimate bearing capacity of the joints,but the thickness of the column wall should not be too large.When the thickness of the column wall is too thick,the shear tensile yield failure of blind bolts will occur.In this case,the limit displacement of the joints can be reduced,and the ductility performance of the joints will decline.So it is recommended that the thickness of column wall should be10-14 mm.(2)The setting of stiffener can obviously improve the ultimate bearing capacity of the nodes,but it has little impact on the initial stiffness of the nodes.In addition,the thickness of the stiffener has little impact on the mechanical properties of the nodes.Therefore,it is recommended that the thickness of the stiffener be 4-8mm for economic and structural reasons.(3)For this kind of joints,the beam is not the weak part of the joints.Reasonable weakening of the flange and web of the beam can ensure that the ultimate bearing capacity and initial rotational stiffness of the joints are basically unchanged.Therefore,in practical engineering applications,reasonable weakening of the beam can be considered to improve the steel utilization rate and save steel.(4)The influence of web height variation on the ultimate bearing capacity and initial rotational stiffness of beams is obvious.The ultimate bearing capacity and initial rotational stiffness of the joints with reduced the beam web height are reduced.In practical application,the section size of the beams should be selected reasonably to obtain better mechanical properties of the joints. |
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